Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755825Ab2EGIef (ORCPT ); Mon, 7 May 2012 04:34:35 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:48512 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755658Ab2EGIee (ORCPT ); Mon, 7 May 2012 04:34:34 -0400 MIME-Version: 1.0 In-Reply-To: References: <20120501132409.GA22894@lizard> <20120501132620.GC24226@lizard> <4FA35A85.4070804@kernel.org> <20120504073810.GA25175@lizard> From: KOSAKI Motohiro Date: Mon, 7 May 2012 04:26:00 -0400 Message-ID: Subject: Re: [PATCH 3/3] vmevent: Implement special low-memory attribute To: Pekka Enberg Cc: Anton Vorontsov , Minchan Kim , Leonid Moiseichuk , John Stultz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1141 Lines: 24 >> If we'll give up on "1." (Pekka, ping), then we need to solve "2." >> in a sane way: we'll have to add a 'NR_FILE_PAGES - NR_SHMEM - >> ' attribute, and give it a name. > > Well, no, we can't give up on (1) completely. That'd mean that > eventually we'd need to change the ABI and break userspace. The > difference between exposing internal details and reasonable > abstractions is by no means black and white. > > AFAICT, RECLAIMABLE_CACHE_PAGES is a reasonable thing to support. Can > anyone come up with a reason why we couldn't do that in the future? It can. but the problem is, that is completely useless. Because of, 1) dirty pages writing-out is sometimes very slow and 2) libc and some important library's pages are critical important for running a system even though it is clean and reclaimable. In other word, kernel don't have an info then can't expose it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/